1. Field of the Invention
The present invention relates generally to the field of internal combustion engines and engine parts. More specifically the present invention relates to a throttle having a throttle body with a tubular throttle body side wall defining a throttle body air passageway for containing an air flow path delivering air into at least one internal combustion engine cylinder, and a flow regulating mechanism comprising an annular diaphragm valve similar in configuration to an iris diaphragm camera shutter and including thick valve blades or plates fitted into a circumferential mounting recess in the throttle body side wall interior surface to be co-planar and providing a valve opening of selectively increasing or decreasing cross-sectional area, the opening being concentric with the throttle body air passageway and substantially symmetrical, thereby regulating air flow while minimizing turbulence.
The blades are configured and mounted so that as they converge to close the throttle, throughout their intermediate positions between fully open and fully closed, the define a substantially star-shaped opening. The arms of the star shape are uniformly arched along their lengths either all clockwise or all counter-clockwise, and as a result are believed to cause air passing through the partially open valve to swirl and define a vortex for enhanced engine performance. The mounting recess preferably is sufficiently deep radially that the valve blades are entirely retracted out of the air flow passageway when the valve is fully open. The mounting recess preferably is a stepped jog in the throttle body side wall interior surface.
The valve includes a stationary bottom plate, having a bottom plate upper face and preferably having a plate retaining flange protruding upwardly from the periphery of the bottom plate upper face, the stationary bottom plate preferably being fixedly attached to an engine intake manifold over and in fluid communication with the manifold intake opening. An annular rotatable actuator plate having an actuator plate central opening is rotatably retained on the bottom plate upper face and within the plate retaining flange. The annular actuator plate includes a circumferential series of arched pin travel slots.
A circumferential series of the valve blades rest flat on top of the actuator plate upper face, each blade having a downwardly protruding travel pin extending into a corresponding one of the travel slots, and each blade having an upwardly protruding fixed pivot pin. The curvature of each pin travel slot necessarily substantially follows an arc defined by the movement of the travel pin when the blade is pivoted about the fixed pivot pin. The preferred number of blades and pin travel slots is five. Each blade has an elongate and generally triangular and curved blade free, end for pivotally extending into the throttle body air passageway and a blade mounted end from which the fixed pivot pin extends.
An annular fixed top plate structure includes top plate having a central top plate opening of the same diameter and shape as, and registering with, the actuator plate opening, the bottom plate opening and includes a breather tube surrounding the top plate opening and extending upwardly from the top plate along the perimeter of the opening. The circumferential series of pin receiving holes are provided in the top plate structure lower face and the fixed pivot pin of each blade fits into a corresponding one of the pin receiving holes such that the blade is pivotable about its fixed pivot pin. The top plate structure abuts and is fixedly fastened to the bottom plate retaining flange, so that the top and bottom plates are rotationally fixed relative to each other and relative to an intake manifold to which the throttle may be attached. The actuator plate is rotatably contained between the stationary bottom plate and the fixed top plate structure.
As a result of this construction, rotation of the actuator plate relative to the top and bottom plates causes each travel pin to bear against a side of the corresponding travel slot and pivot the blades simultaneously around their respective fixed pivot pins so that the blades either pivot toward the common center of the blades to progressively close the valve, or away from the common center of the blades to a position over and along the actuator plate first face to progressively open the valve.
A metered fuel delivery assembly opening into the air passageway is optionally provided, so that the throttle becomes a carburetor.
2. Description of the Prior Art
There have long been throttles with throttle bodies for regulating air flow into the cylinders of internal combustion engines. For many decades such throttle bodies have been provided on automobile engines, in most instances being incorporated into carburetors. Within the generally tubular throttle bodies a butterfly valve plate with a diametrically protruding stem has almost invariably been pivotally mounted to the throttle body side wall and pivoted such as by linkages moved by accelerator depression and by electronic throttle control. See definition of Throttle Body in the WIKIPEDIA.COM™ on-line dictionary. A problem with these prior throttle bodies has been that the butterfly valve extends through the middle of the flow path and significantly obstructs air flow even when the valve is fully open, causing substantial drag and turbulence. What is needed is a throttle body valve which closes uniformly radially inward from the throttle body side wall at once to form a central and substantially circular variable diameter orifice with no central obstruction. To this end, applicant proposes re-structuring an iris diaphragm camera shutter into a throttle body valve, replacing the butterfly valve.
An example of an iris shutter is that disclosed in U.S. Patent Publication Number 2004/0239797 filed by Masuda on May 19, 2004 for a shutter-driving device combined with a diaphragm.
Applicant also has indirect information suggesting that a throttle having a sliding gate valve may have been provided in Great Britain, but has no actual reference to verify or to illustrate this. Should such a valve have been provided, it could not provide an opening which is in all positions generally circular or symmetrical, or one which is continually centered within the air flow path. As a result, air flow with minimized turbulence and drag is not provided.
It is thus an object of the present invention to provide a throttle having a throttle valve which creates minimal drag and turbulence in the air flow stream through a throttle body so that air is delivered into engine cylinders with maximum efficiency.
It is another object of the present invention to provide such a throttle valve which creates such improved flow efficiency by providing and maintaining an unobstructed valve opening.
It is still another object of the present invention to provide such a throttle valve which creates a valve opening which is substantially circular or polygon opening at all degrees of valve opening so that air passes uniformly and evenly through a symmetrical valve opening and air flow is smooth and laminar to the fullest extent possible.
It is yet another object of the present invention to provide such a throttle valve which gives enhanced efficiency at full throttle, as well as at partial throttle.
It is a still further object of the present invention to provide such a throttle valve which can have a smaller diameter inlet hole than a prior butterfly valve of equivalent capacity.
It is a yet further object of the present invention to provide center-feed air flow, and where desired, center-feed air flow, that is air flow from the center outward, with a twist to create a vortex in the air flow.
It is finally an object of the present invention to provide such a throttle which is sturdy, durable, reliable, compact, and cost effective to manufacture.